A cemented carbide and a cermet alloy are materials having high melting points. In order to obtain a cemented carbide sintered compact or a cermet alloy sintered compact, a powder metallurgy method of press-molding or CIP-molding (cold isostatic pressing) a powder raw material and thereafter sintering the same, have generally been employed. In the known methods, however, manufacturable configurations are significantly restricted. In order to obtain a complicated final configuration, it is necessary to grind the sintered compact with a diamond grindstone after sintering, leading to an extremely high cost, due to the hardness of the sintered material.
A technique of molding plastic by an injection molding method is also known. Japanese Patent Publication No. 62-33282 discloses a method of kneading metal powder or ceramics powder with an organic binder and shaping the same into an article having a complicated configuration, by injection molding.
When such a powder injection molding technique is applied to a cemented carbide or a cermet alloy, however, the following problems occur. Cemented carbide powder or cermet alloy powder is a fine powder having a particle diameter of about 1 .mu.m. Further, such an alloy has a large gravity. In addition, the tolerance for a carbon concentration in the alloy is small. Due to such material properties of the cemented carbide or the cermet alloy, deformations and imperfections are easily caused during the debinder processing for removal of the organic binder. Besides, it is impossible to obtain an alloy of good quality, due to an influence exerted by residual carbon which is caused by decomposition of the organic binder. In order to avoid such problems, it is necessary to perform the binder removal processing for an extremely long time. Due to the aforementioned problems, an injection molding technique for a cemented carbide and a cermet alloy has not yet been substantially put into practice.